The present invention relates to an automatic water supply system and, more particularly, to a pneumatic tank type automatic water supplying system in which a pneumatic tank is charged with excessive air.
It is known that an excessive charge of a pneumatic tank of automatic water supply system increases the effective volume of the tank to permit an efficient use of the tank.
However, if the pneumatic tank is used with excessive air charged therein, the air is inconveniently discharged from the tank into the water service pipe when the water level has come down, i.e. when the internal pressure of the pneumatic tank has become low. This air is mixed with the water in the water service pipe to splash the water when the latter is discharged from the faucet to give the user an unpleasant feeling.
An example of pneumatic tank type automatic water supplying system capable of overcoming this problem is shown in Japanese Patent Publication No. 43285/1974. This system is provided with a water-level responsive type valve, i.e. float valve, adapted to close the water outlet port of the pneumatic tank when the water level has come down below a predetermined level, in order to prevent the discharge of air into the water service pipe. This float valve, however, shakes due to a change in the flow of water within the tank, so that the air is released into the water service pipe when the water level in the pressure tank has come down, resulting in an intermittant or a fluctuating of the rate of water supply.